CHENNAI: The Indian Space Research Organisation (ISRO) on Sunday successfully tested its own scramjet+ - an engine that takes atmospheric oxygen to burn engine fuel - a senior ISRO official said.

Two scramjet engines took off from the rocket port located at Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh.

"We are the fourth country to do such a thing, the test (scramjet engine) was very successful," ISRO chairman AS Kiran Kumar.

"Two scramjet engines were tested during the flight. The scramjet engines were ignited 55 seconds into the rocket's flight. The engines were tested for six seconds," a senior ISRO official told IANS.

The engine, used only during the atmospheric phase of a rocket's flight, will help bring down launch costs by reducing the amount of oxidiser that needs to be carried along with fuel. It will eventually be used to power ISRO's reusable launch vehicle (RLV) at hypersonic speed.

ISRO scientists said that the engine, by using atmospheric oxygen, will eventually reduce the weight of the vehicle during lift-off by more than half, enabling it to carry heavier payloads into orbit. The scramjet engine is ideally suited for launch vehicles moving at hypersonic speed.

How it works

Unlike conventional rocket engines which carry both fuel and oxidiser, the scramjet engine with its air-breathing propulsion system technology will forcefully compress atmospheric oxygen when the rocket is in supersonic speed. The atmospheric oxygen will act as an oxidiser to burn the fuel (liquid hydrogen) being carried.

Director of Vikram Sarabhai Space Centre K Sivan told TOI earlier that the experiment is important, as the engine will eventually be used in the RLV.

"The ignition of the engine, the building up of pressure and the duration for which the engine can sustain the flame will be tested and monitored," he said. "The main concern is igniting the air-breathing engine in the air and then sustaining the flame at supersonic speed. If we can sustain it for five seconds, then it can last for even 1000 seconds."

"It can be used in the ascent and descent of the RLV when the vehicle is in the atmospheric phase where oxygen would be available," Sivan added.

Following the test on Sunday, the scramjet engine will be tested on a full-scale RLV, while the vehicle will be tested for its ability to land on a runway.

While many countries like Japan, China, Russia and Europe are in the initial or testing phase of supersonic combustor technology, NASA demonstrated scramjet propulsion in 2004. ISRO had previously carried out a ground test of a scramjet engine in 2006.